Level Of Frost Resistance Research Articles

Frost hardiness of flower buds of 16 apricot cultivars during dormancy

ABSTRACT The effectiveness of apricot cultivation is greatly threatened by frost damage to flower buds during the dormancy period. One of the most important aspects of the evaluation of cultivars is therefore the determination of their frost tolerance. In this paper, the frost hardiness of flower buds of 16 apricot cultivars was investigated in three dormancy periods, applying a standardised artificial freezing test protocol and determining LT50 values. The results showed that both the genotypes and the yearly climatic conditions had a significant effect on frost tolerance. A genotype generally determines the potential maximum of its frost tolerance (‘Sweet Red’ and ‘Primaya’ were very sensitive to frost every year, while ‘Harlayne’ and ‘Rózskajszi C.1406’ could be considered as frost hardy). Flower buds can reach different levels of frost resistance each year depending on the temperature conditions during the hardening and dehardening periods. From the point of view of yield security, it is essential when planning an orchard, to take into account and harmonise the frost hardiness of the cultivars selected and the growing site conditions. Therefore, it is very important to have adequate information about the frost hardiness of different apricot cultivars, which should be included in cultivar descriptions. This paper is intended to contribute to this goal.

Influence of 5-aminolevulinic acid on physiological and biochemical characteristics of winter wheat varieties with different levels of anthocyanins in coleoptiles

Physiological and biochemical characteristics of two varieties of winter wheat seedlings with red (Et W5) and green (Vladi) coleoptiles have been studied. Variety Et W5 with high content of anthocyanins (on average 412 ± 52 μmol/g fr wt), chlorophylls (Chl) and carotenoids and a low level of heme and proline in coleoptiles had high frost resistance (88 % of surviving plants exposed to temperatures of ‒8 °C for 5 h at the age of 7 days) and a high ability to continue growth and development after undergoing cooling. Variety Vladi with a low content of anthocyanins (on average 12.5 ± 1.2 μmol/g fr wt), Chl and carotenoids, but a higher level of heme and proline in coleoptiles compared to varieties Et W5 had low level of frost resistance (80 % of surviving plants) and was characterized by a low ability to continue growth and development after undergoing cooling. Soaking wheat seeds in a solution of exogenous ALA (50 mg/l) for 2 h before sowing increased the germination of seeds of both varieties, enhanced the length of plants of the Et W5 variety by 10 %, 1.4 times the content of anthocyanins in the coleoptiles of this variety plants and also increased their frost resistance up to 97 %. Under action of ALA frost resistance of Vladi seedlings increased up to 93 %.

Relationship of the level of frost resistance and the photosynthetic pigments content in the leaves of winter wheat

Relationship of the level of frost resistance and the photosynthetic pigments content in the leaves of winter wheat

Freezing tolerance of bread winter wheat and its relation with morphological features

In recent years there have been significant changes in weather conditions during wheat growth and development. The aim of the study was to establish the relationship between the level of freezing tolerance of bread winter wheat varieties and their morphological features. The study was conducted during 2016–2019 at the V.M. Remeslo Myronivka Institute of Wheat. 19 bread winter wheat varieties bred at Myronivka were studied. Freezing tolerance of plants was determined according to DSTU 4749:2007 which based on freezing wheat plants in chambers at -18 ºC and -20 ºC with pre-hardening in the open field. The high-frost-tolerant wheat variety Myronivska 808 was used as standard of freezing tolerance. Statistical data processing was performed according to Fisher’s test. Morphological condition of plants was estimated in autumn after vegetation dormancy onset and in spring after its restoration according to the F.M. Kuperman method. The research years were characterized by contrasting weather conditions. It was found that the most bread winter wheat varieties bred at Myronivka have high and medium level of freezing tolerance. Over the years of the research, the elongation of apical cone in the standard variety Myronivska 808 varied from 0.01 to 0.42 mm. In the varieties studied, the elongation of apical cone ranged within 0–0.10 mm (2016– 17), 0.35–0.68 (2017–18) and 0.03–0.32 mm (2018–19). According to the assessment of freezing tolerance, there have been identified valuable bread winter wheat varieties with percent of viable plants over the years of the research exceeding standard variety Myronivska 808 or being at the same level. The varieties MIP Kniazhna, Trudivnytsia myronivska, Lehenda Myronivska, Estafeta myronivska, Vezha myronivska, MIP Dniprianka, MIP Assol were high frost tolerant ones. On average, over the years of the research the varieties MIP Kniazhna, Trudivnytsia myronivska, Lehenda Myronivska, Estafeta myronivska, Vezha myronivska, MIP Dniprianka, and MIP Assol had elongation of apical cone at the level of the Myronivska 808 variety. The variation of the strength and direction of connections between the level of frost resistance and morphological indicators (plant height, length of the growth cone) determined at the time of termination and restoration of winter wheat vegetation was established. Key words: winter wheat, varieties, freezing tolerance, growth, development, apical cone.

СВОБОДНЫЙ ПРОЛИН В ЛИСТЬЯХ КАК ПОКАЗАТЕЛЬ ОПРЕДЕЛЕНИЯ МОРОЗОСТОЙКОСТИ ОЗИМОЙ ПШЕНИЦЫ

Free proline in leaves as an indicator of the determination of winter wheat frost resistance The article considers the results of the determination of frost resistance of winter wheat, grown in the sowing boxes. The amount of plants survived in such conditions (the temperature of freezing was -20 °С) ranged from 20.5 to 83.5% through three years. The standard variety “Tarasovskaya 29” had 55.3% of live plants. The varieties “Polina” (72.3%), “Volnitsa” (76%), “Donskaya bezostaya” (78.1%), “Asket” (78.1%). “Volny Don” (78.3%) and “Don 107” (83.8%) showed high indexes of frost resistance (НСР 05 ± 14.1%). The varieties “Kaprizulya” (37.0%), “Tanya” (38.0%), “Lilit” (38.4%) and “260/09” (20.5%) had low indexes of frost resistance in such conditions. There have been also given the results of the use of an indirect method - a determination of free proline concentration. The content of amino acid in winter wheat leaves during the period from autumn to spring has been determined. More frost tolerant varieties had a larger content of free proline. The content of proline in winter wheat leaves can tell about a level of frost resistance of this or that variety, comparing it with a variety-classifier with a known frost resistance. A close connection of these traits proves this. Thus, the determination of free proline content can become an express method for the determination of the level of winter soft wheat frost resistance. It will allow getting rid of less frost tolerant material during the early stages of the breeding process.

Association of microsatellite loci alleles of the group-5 of chromosomes and the frost resistance of winter wheat

Analysis of frost resistance and microsatellite analysis of the group-5 chromosomes were performed on parental varieties and recombinant-inbred lines F7 Luzanovka odesskaya/Odesskaya krasnokolosaya. Allelic differences for Xcfd7-5B Xwmc415-5B and Xgwm 182-5D microsatellite loci were associated with the level of frost resistance of the lines.

FROST HARDINESS OF PEACH AND APRICOT FLOWER BUDS

The determination of the frost resistance and winter hardiness of peach and apricot varieties is an important task in Hungary, as production can only be competitive if the location and variety are wisely chosen. Various overwintering organs of trees have very different levels of frost resistance, and this resistance also varies greatly over time. During dormancy flower buds are the most frost sensitive organs of peach and apricot trees. From the practical point of view frost resistance and winter hardiness of the flower buds deserve detailed study. The development rate of the overwintering organs of peach and apricot varieties and changes in their frost resistance during the dormancy period have been regularly investigated in recent years in the gene bank collection of Corvinus University of Budapest. The present paper provides an analysis of frost hardiness of flower buds based on the results obtained in three consecutive winters with very diverse weather conditions. The hardening processes of overwintering organs are fundamentally determined by environmental factors, particularly by temperature. Thus, even at the same location, the development rate of the flower buds and the development of frost resistance may differ from year to year. The determination of the maximum frost resistance genetically attainable and the description of changes in frost resistance are only possible in a series of experiments over several years.

Primary and secondary metabolism of winter wheat under cold hardening and treatment with antioxidants

The content of saccharides and phenolic compounds (including flavonoids and lignin) and the activity of L-phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were determined in leaves and tillering nodes of winter wheat Triticum aestivum L.) cultivars Inna and Moskovskaya 39, differing in the level of frost resistance. These parameters were determined in three groups of plants--control, hardened, and treated with synthetic antioxidants (ambiol and amerol 2000). Cold hardening increased accumulation of primary and secondary metabolites in tissues but decreased the enzyme activity. Treatment with antioxidants also increased the content of saccharides and phenolic compounds (primarily flavonoids) and PAL activity. These changes were more pronounced in cultivar Inna, which is less frost resistant than Moskovskaya 39.

S-methylmethionine reduces cell membrane damage in higher plants exposed to low-temperature stress

S-methylmethionine (SMM), an important intermediate compound in the sulphur metabolism, can be found in various quantities in majority of plants. The experiments were designed to determine the extent to which SMM is able to preserve cell membrane integrity or reduce the degree of membrane damage in the course of low-temperature stress. By measuring electrolyte leakage (EL), it was proved that SMM treatment reduced cell membrane damage, and thus EL, during low-temperature stress in both the leaves and roots of peas, maize, soy beans and eight winter wheat varieties with different levels of frost resistance. Investigations on the interaction between SMM and polyamine biosynthesis revealed that SMM increased the quantities of agmatine (Agm) and putrescine (Put) as well as that of spermidine (Spd), while it had no effect on the quantity of spermine (Spn). Using a specific inhibitor, methylglyoxal-bis-guanyl hydrazone (MGBG), it was proved that the polyamine metabolic pathway starting from methionine played no role in the synthesis of Spd or Spn, so there must be an alternative pathway for the synthesis of SMM-induced polyamines.

Frost resistance and cold acclimation abilities of spring-type oilseed rape

Spring forms of oilseed rape are perceived as having low frost resistance. This is consistent with some field observations and laboratory studies in which spring and winter forms showed different extents of metabolic changes during cold acclimation. This is somewhat surprising, since rapeseed cultivars are classified as winter or spring types based on their requirements for vernalization to flower, not on their levels of frost resistance. This discrepancy may be due to the limited abilities of spring-type rape, in commonly used growth conditions, to cease growth and, simultaneously, maintain a high photosynthetic activity during cold acclimation, which is considered necessary for proper hardening. This study was conducted to determine if spring oilseed rape could acclimate to the level observed in winter-type plants after modification of growth and photosynthetic characteristics induced by prehardening. After prehardening spring cultivars of oilseed rape showed frost resistance comparable with winter-type plants and their response to prehardening was even stronger than that in winter-type plants. It is caused by the exceptionally low cold acclimation abilities of non-prehardened spring forms. No differences were noted between the frost resistances of callus tissue derived from winter and spring-type cultivars.

Role of the Chromosome 4B in Suppressing Frost Resistance in Winter Wheat (Triticum aestivum L.)

SUMMARY Frost resistance of different monosomic lines were investigated under controlled environment conditions. In the case of Cheyenne, Mironovskaya 808 and Rannyaya 12 a reduction in the degree of frost resistance was observed when chromosomes 5A, 3B, 3A, 5B or 7A were missing. In two of the monosomic series there was also a drop in the level of frost resistance in monosomic lines 5D and 7B. The frost resistance of monosomic line 4B, on the other hand, was significantly better than that of the disome in two of the three cultivars. In previous experiments using substitution lines, the presence of a 4B chromosome originating from a variety with better frost resistance also led to an increase in frost resistance. The results suggest that a gene suppressor for frost resistance may be located on chromosome 4B

A Genetic Study of Frost Resistance in Wheat Callus Culture

AbstractThe genetic control of frost resistance was studied in callus cultures using some of the chromosome substitution lines of the variety ‘Cheyenne’ into ‘Chinese Spring’. The survival of the calli derived from immature embryos was studied with triphenyltet‐razolium chloride (TTC) and fluorescein diacetate (5DA) methods after hardening and freezing at a temperatures of ‐7 °C, ‐9 °C, ‐11 °C, ‐13 °C, and –15 °C. The donor ‘Cheyenne’ and the substitution lines 5A and 5D proved to be more frost resistant than the recipient ‘Chinese Spring1. These results are well correlated with the previously published studies when seedlings were tested under controlled conditions. Based on these results the tissue culture technique seems to be useful for testing varieties and lines for different levels of frost resistance and even for mutant selection.

Opposite effects of temperature on breaking of dormancy and on induction of frost resistance in apple embryos

Apples (Pyrus mains L., ev. Golden Delicious) were placed at 0, 12 and 35°C. At different intervals, seeds were taken from fruits, and the ability of isolated embryos to germinate was determined. In parallel, the survival of similar embryos frozen for 30 min at ‐7°C was estimated. Storage of apples at 0°C led to complete removal of embryo dormancy within ca 10 weeks. At 12°C, dormancy was only partly eliminated, and at 35°C breaking of dormancy did not occur. The onset of secondary embryo dormancy was thus evident as the result of 35 and 12°C treatments. On the other hand, the storage of apples at 35°C was the most effective treatment for induction of frost resistance in the embryos. At 12°C the same level of frost resistance was reached much slower. Even a prolonged storage of apples at 0°C did not allow frost survival of all embryos. The above relations were confirmed in experiments with transfer of fruits from one temperature of storage to another. The temperature of fruit storage affected the dormancy removal in embryos and induction of resistance to rapid freezing in opposite directions.

Eucalyptus Physiology. III. Frost Resistance.

The effects of different hardening regimes were studied in E. viminalis by varying temperature, light conditions and photoperiod. The role of root temperature in dehardening was investigated in E. grandis. The relationship between leaf glaucousness and frost resistance was reexamined in E. urnigera and in crosses between the glaucous frost-resistant species E. pulverulenta and the green. less-resistant species E. grandis. These studies involved seedlings but adult material was also used when checking the association between frost resistance and G, the growth regulator in E. grandis. Provided that night temperatures were close to freezing, rapid hardening was independent of photoperiod, light source and day/night temperature differentials. No significant relationship between level of frost resistance and intensity of leaf glaucousness was observed in a segregating progeny of E. urnigera. In F2 and backcross progenies between E. pulverulenta and E. grandis, no evidence was obtained for either physiological or genetical links between glaucousness and frost resistance. As in several other Eucalyptus species, low root temperatures delayed rapid dehardening in E. grandis. Increased frost resistance towards the top of E. grandis seedlings was associated with marked ontogenetic increases in G content. The G content of a 2 m sapling was highest in winter when maximum frost resistance had developed. This and other supporting evidence suggests that G has a role in the frost resistance of E. Grandis perhaps by affecting active electron transport properties of membranes. No information of this kind is available for other Eucalyptus species.